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An H, Zhou B, Hayakawa K, Durán Laforet V, Park JH, Nakamura Y, Mandeville ET, Liu N, Guo S, Yu Z, Shi J, Wu D, Li W, Lo EH, Ji X. ATF5-Mediated Mitochondrial Unfolded Protein Response (UPR mt) Protects Neurons Against Oxygen-Glucose Deprivation and Cerebral Ischemia. Stroke 2024; 55:1904-1913. [PMID: 38913800 DOI: 10.1161/strokeaha.123.045550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 05/09/2024] [Indexed: 06/26/2024]
Abstract
BACKGROUND The mitochondrial unfolded protein response (UPRmt) is an evolutionarily conserved mitochondrial response that is critical for maintaining mitochondrial and energetic homeostasis under cellular stress after tissue injury and disease. Here, we ask whether UPRmt may be a potential therapeutic target for ischemic stroke. METHODS We performed the middle cerebral artery occlusion and oxygen-glucose deprivation models to mimic ischemic stroke in vivo and in vitro, respectively. Oligomycin and meclizine were used to trigger the UPRmt. We used 2,3,5-triphenyltetrazolium chloride staining, behavioral tests, and Nissl staining to evaluate cerebral injury in vivo. The Cell Counting Kit-8 assay and the Calcein AM Assay Kit were conducted to test cerebral injury in vitro. RESULTS Inducing UPRmt with oligomycin protected neuronal cultures against oxygen-glucose deprivation. UPRmt could also be triggered with meclizine, and this Food and Drug Administration-approved drug also protected neurons against oxygen-glucose deprivation. Blocking UPRmt with siRNA against activating transcription factor 5 eliminated the neuroprotective effects of meclizine. In a mouse model of focal cerebral ischemia, pretreatment with meclizine was able to induce UPRmt in vivo, which reduced infarction and improved neurological outcomes. CONCLUSIONS These findings suggest that the UPRmt is important in maintaining the survival of neurons facing ischemic/hypoxic stress. The UPRmt mechanism may provide a new therapeutic avenue for ischemic stroke.
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Affiliation(s)
- Hong An
- Department of Neurology, Beijing Chaoyang Hospital, Capital Medical University, China (H.A.)
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
- Cerebrovascular and Neuroscience Research Institute, Xuanwu Hospital, Capital Medical University, Beijing, China (H.A., J.S., D.W., X.J.)
| | - Bing Zhou
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University, China (B.Z.)
| | - Kazuhide Hayakawa
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
| | - Violeta Durán Laforet
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
- Unidad de Investigación Neurovascular, Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid (UCM), Instituto de Investigación Hospital 12 de Octubre, Spain (V.D.L.)
| | - Ji-Hyun Park
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
| | - Yoshihiko Nakamura
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
- Department of Emergency and Critical Care Medicine, Fukuoka University Hospital, Japan (Y.N.)
| | - Emiri T Mandeville
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
| | - Ning Liu
- Clinical Neuroscience Research Center, Department of Neurosurgery and Neurology, Tulane University School of Medicine, New Orleans, LA (N.L.)
| | - Shuzhen Guo
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
| | - Zhanyang Yu
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
| | - Jingfei Shi
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
- Cerebrovascular and Neuroscience Research Institute, Xuanwu Hospital, Capital Medical University, Beijing, China (H.A., J.S., D.W., X.J.)
| | - Di Wu
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
- Cerebrovascular and Neuroscience Research Institute, Xuanwu Hospital, Capital Medical University, Beijing, China (H.A., J.S., D.W., X.J.)
| | - Wenlu Li
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
| | - Eng H Lo
- Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston (H.A., K.H., V.D.L., J.-H.P., Y.N., E.T.M., S.G., Z.Y., J.S., D.W., W.L., E.H.L.)
| | - Xunming Ji
- Cerebrovascular and Neuroscience Research Institute, Xuanwu Hospital, Capital Medical University, Beijing, China (H.A., J.S., D.W., X.J.)
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China (X.J.)
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2
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Makki A, Kereïche S, Le T, Kučerová J, Rada P, Žárský V, Hrdý I, Tachezy J. A hybrid TIM complex mediates protein import into hydrogenosomes of Trichomonas vaginalis. BMC Biol 2024; 22:130. [PMID: 38825681 PMCID: PMC11145794 DOI: 10.1186/s12915-024-01928-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 05/22/2024] [Indexed: 06/04/2024] Open
Abstract
BACKGROUND Hydrogenosomes are a specific type of mitochondria that have adapted for life under anaerobiosis. Limited availability of oxygen has resulted in the loss of the membrane-associated respiratory chain, and consequently in the generation of minimal inner membrane potential (Δψ), and inefficient ATP synthesis via substrate-level phosphorylation. The changes in energy metabolism are directly linked with the organelle biogenesis. In mitochondria, proteins are imported across the outer membrane via the Translocase of the Outer Membrane (TOM complex), while two Translocases of the Inner Membrane, TIM22, and TIM23, facilitate import to the inner membrane and matrix. TIM23-mediated steps are entirely dependent on Δψ and ATP hydrolysis, while TIM22 requires only Δψ. The character of the hydrogenosomal inner membrane translocase and the mechanism of translocation is currently unknown. RESULTS We report unprecedented modification of TIM in hydrogenosomes of the human parasite Trichomonas vaginalis (TvTIM). We show that the import of the presequence-containing protein into the hydrogenosomal matrix is mediated by the hybrid TIM22-TIM23 complex that includes three highly divergent core components, TvTim22, TvTim23, and TvTim17-like proteins. The hybrid character of the TvTIM is underlined by the presence of both TvTim22 and TvTim17/23, association with small Tim chaperones (Tim9-10), which in mitochondria are known to facilitate the transfer of substrates to the TIM22 complex, and the coupling with TIM23-specific ATP-dependent presequence translocase-associated motor (PAM). Interactome reconstruction based on co-immunoprecipitation (coIP) and mass spectrometry revealed that hybrid TvTIM is formed with the compositional variations of paralogs. Single-particle electron microscopy for the 132-kDa purified TvTIM revealed the presence of a single ring of small Tims complex, while mitochondrial TIM22 complex bears twin small Tims hexamer. TvTIM is currently the only TIM visualized outside of Opisthokonta, which raised the question of which form is prevailing across eukaryotes. The tight association of the hybrid TvTIM with ADP/ATP carriers (AAC) suggests that AAC may directly supply ATP for the protein import since ATP synthesis is limited in hydrogenosomes. CONCLUSIONS The hybrid TvTIM in hydrogenosomes represents an original structural solution that evolved for protein import when Δψ is negligible and remarkable example of evolutionary adaptation to an anaerobic lifestyle.
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Affiliation(s)
- Abhijith Makki
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic
- Present address: Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073, Göttingen, Germany
| | - Sami Kereïche
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Albertov 4, 12800, Prague 2, Czech Republic
| | - Tien Le
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic
| | - Jitka Kučerová
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic
| | - Petr Rada
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic
| | - Vojtěch Žárský
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25250, Vestec, Czech Republic.
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3
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Alavi Z, Casanova-Morales N, Quiroga-Roger D, Wilson CAM. Towards the understanding of molecular motors and its relationship with local unfolding. Q Rev Biophys 2024; 57:e7. [PMID: 38715547 DOI: 10.1017/s0033583524000052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Molecular motors are machines essential for life since they convert chemical energy into mechanical work. However, the precise mechanism by which nucleotide binding, catalysis, or release of products is coupled to the work performed by the molecular motor is still not entirely clear. This is due, in part, to a lack of understanding of the role of force in the mechanical-structural processes involved in enzyme catalysis. From a mechanical perspective, one promising hypothesis is the Haldane-Pauling hypothesis which considers the idea that part of the enzymatic catalysis is strain-induced. It suggests that enzymes cannot be efficient catalysts if they are fully complementary to the substrates. Instead, they must exert strain on the substrate upon binding, using enzyme-substrate energy interaction (binding energy) to accelerate the reaction rate. A novel idea suggests that during catalysis, significant strain energy is built up, which is then released by a local unfolding/refolding event known as 'cracking'. Recent evidence has also shown that in catalytic reactions involving conformational changes, part of the heat released results in a center-of-mass acceleration of the enzyme, raising the possibility that the heat released by the reaction itself could affect the enzyme's integrity. Thus, it has been suggested that this released heat could promote or be linked to the cracking seen in proteins such as adenylate kinase (AK). We propose that the energy released as a consequence of ligand binding/catalysis is associated with the local unfolding/refolding events (cracking), and that this energy is capable of driving the mechanical work.
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Affiliation(s)
- Zahra Alavi
- Department of Physics, Loyola Marymount University, Los Angeles, CA, USA
| | | | - Diego Quiroga-Roger
- Biochemistry and Molecular Biology Department, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
| | - Christian A M Wilson
- Biochemistry and Molecular Biology Department, Faculty of Chemistry and Pharmaceutical Sciences, Universidad de Chile, Santiago, Chile
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4
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Mistry AC, Chowdhury D, Chakraborty S, Haldar S. Elucidating the novel mechanisms of molecular chaperones by single-molecule technologies. Trends Biochem Sci 2024; 49:38-51. [PMID: 37980187 DOI: 10.1016/j.tibs.2023.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 11/20/2023]
Abstract
Molecular chaperones play central roles in sustaining protein homeostasis and preventing protein aggregation. Most studies of these systems have been performed in bulk, providing averaged measurements, though recent single-molecule approaches have provided an in-depth understanding of the molecular mechanisms of their activities and structural rearrangements during substrate recognition. Chaperone activities have been observed to be substrate specific, with some associated with ATP-dependent structural dynamics and others via interactions with co-chaperones. This Review aims to describe the novel mechanisms of molecular chaperones as revealed by single-molecule approaches, and to provide insights into their functioning and its implications for protein homeostasis and human diseases.
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Affiliation(s)
- Ayush Chandrakant Mistry
- Department of Biology, Trivedi School of Biosciences, Ashoka University, Sonepat, Haryana 131029, India
| | - Debojyoti Chowdhury
- Department of Chemical and Biological Sciences, S.N. Bose National Center for Basic Sciences, Kolkata, West Bengal 700106, India
| | - Soham Chakraborty
- Department of Biology, Trivedi School of Biosciences, Ashoka University, Sonepat, Haryana 131029, India
| | - Shubhasis Haldar
- Department of Biology, Trivedi School of Biosciences, Ashoka University, Sonepat, Haryana 131029, India; Department of Chemical and Biological Sciences, S.N. Bose National Center for Basic Sciences, Kolkata, West Bengal 700106, India; Department of Chemistry, Ashoka University, Sonepat, Haryana 131029, India.
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5
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Hartmann A, Sreenivasa K, Schenkel M, Chamachi N, Schake P, Krainer G, Schlierf M. An automated single-molecule FRET platform for high-content, multiwell plate screening of biomolecular conformations and dynamics. Nat Commun 2023; 14:6511. [PMID: 37845199 PMCID: PMC10579363 DOI: 10.1038/s41467-023-42232-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 10/03/2023] [Indexed: 10/18/2023] Open
Abstract
Single-molecule FRET (smFRET) has become a versatile tool for probing the structure and functional dynamics of biomolecular systems, and is extensively used to address questions ranging from biomolecular folding to drug discovery. Confocal smFRET measurements are amongst the widely used smFRET assays and are typically performed in a single-well format. Thus, sampling of many experimental parameters is laborious and time consuming. To address this challenge, we extend here the capabilities of confocal smFRET beyond single-well measurements by integrating a multiwell plate functionality to allow for continuous and automated smFRET measurements. We demonstrate the broad applicability of the multiwell plate assay towards DNA hairpin dynamics, protein folding, competitive and cooperative protein-DNA interactions, and drug-discovery, revealing insights that would be very difficult to achieve with conventional single-well format measurements. For the adaptation into existing instrumentations, we provide a detailed guide and open-source acquisition and analysis software.
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Affiliation(s)
- Andreas Hartmann
- B CUBE Center for Molecular Bioengineering, TU Dresden, Tatzberg 41, 01307, Dresden, Germany.
| | - Koushik Sreenivasa
- B CUBE Center for Molecular Bioengineering, TU Dresden, Tatzberg 41, 01307, Dresden, Germany
- Department of Bionanoscience, Delft University of Technology, 2629HZ, Delft, Netherlands
| | - Mathias Schenkel
- B CUBE Center for Molecular Bioengineering, TU Dresden, Tatzberg 41, 01307, Dresden, Germany
| | - Neharika Chamachi
- B CUBE Center for Molecular Bioengineering, TU Dresden, Tatzberg 41, 01307, Dresden, Germany
| | - Philipp Schake
- B CUBE Center for Molecular Bioengineering, TU Dresden, Tatzberg 41, 01307, Dresden, Germany
| | - Georg Krainer
- B CUBE Center for Molecular Bioengineering, TU Dresden, Tatzberg 41, 01307, Dresden, Germany
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW, Cambridge, UK
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/III, 8010, Graz, Austria
| | - Michael Schlierf
- B CUBE Center for Molecular Bioengineering, TU Dresden, Tatzberg 41, 01307, Dresden, Germany.
- Physics of Life, DFG Cluster of Excellence, TU Dresden, 01062, Dresden, Germany.
- Faculty of Physics, TU Dresden, 01062, Dresden, Germany.
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6
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Ciesielski SJ, Young C, Ciesielska EJ, Ciesielski GL. The Hsp70 and JDP proteins: Structure-function perspective on molecular chaperone activity. Enzymes 2023; 54:221-245. [PMID: 37945173 DOI: 10.1016/bs.enz.2023.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Proteins are the most structurally diverse cellular biomolecules that act as molecular machines driving essential activities of all living organisms. To be functional, most of the proteins need to fold into a specific three-dimensional structure, which on one hand should be stable enough to oppose disruptive conditions and on the other hand flexible enough to allow conformational dynamics necessary for their biological functions. This compromise between stability and dynamics makes proteins susceptible to stress-induced misfolding and aggregation. Moreover, the folding process itself is intrinsically prone to conformational errors. Molecular chaperones are proteins that mitigate folding defects and maintain the structural integrity of the cellular proteome. Promiscuous Hsp70 chaperones are central to these processes and their activity depends on the interaction with obligatory J-domain protein (JDP) partners. In this review, we discuss structural aspects of Hsp70s, JDPs, and their interaction in the context of biological activities.
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Affiliation(s)
- Szymon J Ciesielski
- Department of Chemistry and Biochemistry, University of North Florida, Jacksonville, FL, United States.
| | - Cameron Young
- Department of Chemistry and Biochemistry, University of North Florida, Jacksonville, FL, United States
| | - Elena J Ciesielska
- Department of Chemistry, Auburn University at Montgomery, Montgomery, AL, United States; Department of Biology, University of North Florida, Jacksonville, FL, United States
| | - Grzegorz L Ciesielski
- Department of Chemistry, Auburn University at Montgomery, Montgomery, AL, United States; Department of Biology, University of North Florida, Jacksonville, FL, United States
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7
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Makki A, Rehling P. Protein transport along the presequence pathway. Biol Chem 2023; 404:807-812. [PMID: 37155927 DOI: 10.1515/hsz-2023-0133] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 04/25/2023] [Indexed: 05/10/2023]
Abstract
Most mitochondrial proteins are nuclear-encoded and imported by the protein import machinery based on specific targeting signals. The proteins that carry an amino-terminal targeting signal (presequence) are imported via the presequence import pathway that involves the translocases of the outer and inner membranes - TOM and TIM23 complexes. In this article, we discuss how mitochondrial matrix and inner membrane precursor proteins are imported along the presequence pathway in Saccharomyces cerevisiae with a focus on the dynamics of the TIM23 complex, and further update with some of the key findings that advanced the field in the last few years.
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Affiliation(s)
- Abhijith Makki
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
- Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Translational Neuroinflammation and Automated Microscopy, Göttingen, Germany
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8
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Almaazmi SY, Kaur RP, Singh H, Blatch GL. The Plasmodium falciparum exported J domain proteins fine-tune human and malarial Hsp70s: pathological exploitation of proteostasis machinery. Front Mol Biosci 2023; 10:1216192. [PMID: 37457831 PMCID: PMC10349383 DOI: 10.3389/fmolb.2023.1216192] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 06/12/2023] [Indexed: 07/18/2023] Open
Abstract
Cellular proteostasis requires a network of molecular chaperones and co-chaperones, which facilitate the correct folding and assembly of other proteins, or the degradation of proteins misfolded beyond repair. The function of the major chaperones, heat shock protein 70 (Hsp70) and heat shock protein 90 (Hsp90), is regulated by a cohort of co-chaperone proteins. The J domain protein (JDP) family is one of the most diverse co-chaperone families, playing an important role in functionalizing the Hsp70 chaperone system to form a powerful protein quality control network. The intracellular malaria parasite, Plasmodium falciparum, has evolved the capacity to invade and reboot mature human erythrocytes, turning them into a vehicles of pathology. This process appears to involve the harnessing of both the human and parasite chaperone machineries. It is well known that malaria parasite-infected erythrocytes are highly enriched in functional human Hsp70 (HsHsp70) and Hsp90 (HsHsp90), while recent proteomics studies have provided evidence that human JDPs (HsJDPs) may also be enriched, but at lower levels. Interestingly, P. falciparum JDPs (PfJDPs) are the most prominent and diverse family of proteins exported into the infected erythrocyte cytosol. We hypothesize that the exported PfJPDs may be an evolutionary consequence of the need to boost chaperone power for specific protein folding pathways that enable both survival and pathogenesis of the malaria parasite. The evidence suggests that there is an intricate network of PfJDP interactions with the exported malarial Hsp70 (PfHsp70-x) and HsHsp70, which appear to be important for the trafficking of key malarial virulence factors, and the proteostasis of protein complexes of human and parasite proteins associated with pathology. This review will critically evaluate the current understanding of the role of exported PfJDPs in pathological exploitation of the proteostasis machinery by fine-tuning the chaperone properties of both human and malarial Hsp70s.
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Affiliation(s)
- Shaikha Y. Almaazmi
- Biomedical Research and Drug Discovery Research Group, Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
| | - Rupinder P. Kaur
- The Department of Chemistry, Guru Nanak Dev University College Verka, Amritsar, Punjab, India
| | - Harpreet Singh
- Department of Bioinformatics, Hans Raj Mahila Maha Vidyalaya, Jalandhar, Punjab, India
| | - Gregory L. Blatch
- Biomedical Research and Drug Discovery Research Group, Faculty of Health Sciences, Higher Colleges of Technology, Sharjah, United Arab Emirates
- Biomedical Biotechnology Research Unit, Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, South Africa
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9
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Song J, Steidle L, Steymans I, Singh J, Sanner A, Böttinger L, Winter D, Becker T. The mitochondrial Hsp70 controls the assembly of the F 1F O-ATP synthase. Nat Commun 2023; 14:39. [PMID: 36596815 PMCID: PMC9810599 DOI: 10.1038/s41467-022-35720-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 12/20/2022] [Indexed: 01/04/2023] Open
Abstract
The mitochondrial F1FO-ATP synthase produces the bulk of cellular ATP. The soluble F1 domain contains the catalytic head that is linked via the central stalk and the peripheral stalk to the membrane embedded rotor of the FO domain. The assembly of the F1 domain and its linkage to the peripheral stalk is poorly understood. Here we show a dual function of the mitochondrial Hsp70 (mtHsp70) in the formation of the ATP synthase. First, it cooperates with the assembly factors Atp11 and Atp12 to form the F1 domain of the ATP synthase. Second, the chaperone transfers Atp5 into the assembly line to link the catalytic head with the peripheral stalk. Inactivation of mtHsp70 leads to integration of assembly-defective Atp5 variants into the mature complex, reflecting a quality control function of the chaperone. Thus, mtHsp70 acts as an assembly and quality control factor in the biogenesis of the F1FO-ATP synthase.
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Affiliation(s)
- Jiyao Song
- Institute for Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany.,Institute for Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Liesa Steidle
- Institute for Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Isabelle Steymans
- Institute for Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Jasjot Singh
- Institute for Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Anne Sanner
- Institute for Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Lena Böttinger
- Institute for Biochemistry and Molecular Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Dominic Winter
- Institute for Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Thomas Becker
- Institute for Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany.
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10
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Marszalek J, Craig EA, Tomiczek B. J-Domain Proteins Orchestrate the Multifunctionality of Hsp70s in Mitochondria: Insights from Mechanistic and Evolutionary Analyses. Subcell Biochem 2023; 101:293-318. [PMID: 36520311 DOI: 10.1007/978-3-031-14740-1_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Mitochondrial J-domain protein (JDP) co-chaperones orchestrate the function of their Hsp70 chaperone partner(s) in critical organellar processes that are essential for cell function. These include folding, refolding, and import of mitochondrial proteins, maintenance of mitochondrial DNA, and biogenesis of iron-sulfur cluster(s) (FeS), prosthetic groups needed for function of mitochondrial and cytosolic proteins. Consistent with the organelle's endosymbiotic origin, mitochondrial Hsp70 and the JDPs' functioning in protein folding and FeS biogenesis clearly descended from bacteria, while the origin of the JDP involved in protein import is less evident. Regardless of their origin, all mitochondrial JDP/Hsp70 systems evolved unique features that allowed them to perform mitochondria-specific functions. Their modes of functional diversification and specialization illustrate the versatility of JDP/Hsp70 systems and inform our understanding of system functioning in other cellular compartments.
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Affiliation(s)
- Jaroslaw Marszalek
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland.
| | - Elizabeth A Craig
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
| | - Bartlomiej Tomiczek
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
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11
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Miyake M, Sobajima M, Kurahashi K, Shigenaga A, Denda M, Otaka A, Saio T, Sakane N, Kosako H, Oyadomari S. Identification of an endoplasmic reticulum proteostasis modulator that enhances insulin production in pancreatic β cells. Cell Chem Biol 2022; 29:996-1009.e9. [PMID: 35143772 DOI: 10.1016/j.chembiol.2022.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 11/11/2021] [Accepted: 01/06/2022] [Indexed: 12/13/2022]
Abstract
Perturbation of endoplasmic reticulum (ER) proteostasis is associated with impairment of cellular function in diverse diseases, especially the function of pancreatic β cells in type 2 diabetes. Restoration of ER proteostasis by small molecules shows therapeutic promise for type 2 diabetes. Here, using cell-based screening, we report identification of a chemical chaperone-like small molecule, KM04794, that alleviates ER stress. KM04794 prevented protein aggregation and cell death caused by ER stressors and a mutant insulin protein. We also found that this compound increased intracellular and secreted insulin levels in pancreatic β cells. Chemical biology and biochemical approaches revealed that the compound accumulated in the ER and interacted directly with the ER molecular chaperone BiP. Our data show that this corrector of ER proteostasis can enhance insulin storage and pancreatic β cell function.
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Affiliation(s)
- Masato Miyake
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan; Department of Molecular Research, Diabetes Therapeutics and Research Center, Tokushima University, Tokushima, Japan; Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan.
| | - Mitsuaki Sobajima
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan; Department of Molecular Research, Diabetes Therapeutics and Research Center, Tokushima University, Tokushima, Japan
| | - Kiyoe Kurahashi
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan; Department of Molecular Research, Diabetes Therapeutics and Research Center, Tokushima University, Tokushima, Japan; Department of Hematology, Endocrinology and Metabolism, Graduate School of Biomedical Sciences, Tokushima University, Tokushima, Japan
| | - Akira Shigenaga
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences, Tokushima University, Tokushima, Japan; Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Hiroshima, Japan
| | - Masaya Denda
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences, Tokushima University, Tokushima, Japan
| | - Akira Otaka
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences, Tokushima University, Tokushima, Japan
| | - Tomohide Saio
- Division of Molecular Life Science, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan; Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Naoki Sakane
- Pharmaceutical Frontier Research Laboratories, JT Inc., Yokohama, Japan
| | - Hidetaka Kosako
- Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Seiichi Oyadomari
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan; Department of Molecular Research, Diabetes Therapeutics and Research Center, Tokushima University, Tokushima, Japan; Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan.
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12
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Abstract
Mitochondria play a central role in the pathophysiological processes of acute ischemic stroke. Disruption of the cerebral blood flow during acute ischemic stroke interrupts oxygen and glucose delivery, leading to the dysfunction of mitochondrial oxidative phosphorylation and cellular bioenergetic stress. Cells can respond to such stress by activating mitochondrial quality control mechanisms, including the mitochondrial unfolded protein response, mitochondrial fission and fusion, mitophagy, mitochondrial biogenesis, and intercellular mitochondrial transfer. Collectively, these adaptive response strategies contribute to retaining the integrity and function of the mitochondrial network, thereby helping to recover the homeostasis of the neurovascular unit. In this review, we focus on mitochondrial quality control mechanisms occurring in acute ischemic stroke. A better understanding of how these regulatory pathways work in maintaining mitochondrial homeostasis will provide a rationale for developing innovative neuroprotectants when these mechanisms fail in acute ischemic stroke.
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Affiliation(s)
- Hong An
- Department of Neurology and China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Bing Zhou
- Department of Neurology and China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University, Beijing, China.,Interdisciplinary Innovation Institute of Medicine and Engineering Interdisciplinary, Beihang University, Beijing, China
| | - Xunming Ji
- Department of Neurology and China-America Institute of Neuroscience, Xuanwu Hospital, Capital Medical University, Beijing, China.,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University, Beijing, China.,Interdisciplinary Innovation Institute of Medicine and Engineering Interdisciplinary, Beihang University, Beijing, China.,Department of Neurosurgery, 71044Xuanwu Hospital, Xuanwu Hospital, Capital Medical University, Beijing, China
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13
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Comparative analysis of the coordinated motion of Hsp70s from different organelles observed by single-molecule three-color FRET. Proc Natl Acad Sci U S A 2021; 118:2025578118. [PMID: 34389669 DOI: 10.1073/pnas.2025578118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Cellular function depends on the correct folding of proteins inside the cell. Heat-shock proteins 70 (Hsp70s), being among the first molecular chaperones binding to nascently translated proteins, aid in protein folding and transport. They undergo large, coordinated intra- and interdomain structural rearrangements mediated by allosteric interactions. Here, we applied a three-color single-molecule Förster resonance energy transfer (FRET) combined with three-color photon distribution analysis to compare the conformational cycle of the Hsp70 chaperones DnaK, Ssc1, and BiP. By capturing three distances simultaneously, we can identify coordinated structural changes during the functional cycle. Besides the known conformations of the Hsp70s with docked domains and open lid and undocked domains with closed lid, we observed additional intermediate conformations and distance broadening, suggesting flexibility of the Hsp70s in adopting the states in a coordinated fashion. Interestingly, the difference of this distance broadening varied between DnaK, Ssc1, and BiP. Study of their conformational cycle in the presence of substrate peptide and nucleotide exchange factors strengthened the observation of additional conformational intermediates, with BiP showing coordinated changes more clearly compared to DnaK and Ssc1. Additionally, DnaK and BiP were found to differ in their selectivity for nucleotide analogs, suggesting variability in the recognition mechanism of their nucleotide-binding domains for the different nucleotides. By using three-color FRET, we overcome the limitations of the usual single-distance approach in single-molecule FRET, allowing us to characterize the conformational space of proteins in higher detail.
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14
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The HSP70 chaperone as sensor of the NEDD8 cycle upon DNA damage. Biochem Soc Trans 2021; 49:1075-1083. [PMID: 34156462 DOI: 10.1042/bst20200381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/13/2021] [Accepted: 04/15/2021] [Indexed: 11/17/2022]
Abstract
Molecular chaperones are essential components of the protein quality control system and maintenance of homeostasis. Heat Shock Protein 70 (HSP70), a highly evolutionarily conserved family of chaperones is a key regulator of protein folding, oligomerisation and prevents the aggregation of misfolded proteins. HSP70 chaperone function depends on the so-called 'HSP70-cycle', where HSP70 interacts with and is released from substrates via ATP hydrolysis and the assistance of HSP70 co-factors/co-chaperones, which also provide substrate specificity. The identification of regulatory modules for HSP70 allows the elucidation of HSP70 specificity and target selectivity. Here, we discuss how the HSP70 cycle is functionally linked with the cycle of the Ubiquitin-like molecule NEDD8. Using as an example the DNA damage response, we present a model where HSP70 acts as a sensor of the NEDD8 cycle. The NEDD8 cycle acts as a regulatory module of HSP70 activity, where conversion of poly-NEDD8 chains into mono-NEDD8 upon DNA damage activates HSP70, facilitating the formation of the apoptosome and apoptosis execution.
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15
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Maity S, Chakrabarti O. Mitochondrial protein import as a quality control sensor. Biol Cell 2021; 113:375-400. [PMID: 33870508 DOI: 10.1111/boc.202100002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/04/2021] [Accepted: 04/09/2021] [Indexed: 12/17/2022]
Abstract
Mitochondria are organelles involved in various functions related to cellular metabolism and homoeostasis. Though mitochondria contain own genome, their nuclear counterparts encode most of the different mitochondrial proteins. These are synthesised as precursors in the cytosol and have to be delivered into the mitochondria. These organelles hence have elaborate machineries for the import of precursor proteins from cytosol. The protein import machineries present in both mitochondrial membrane and aqueous compartments show great variability in pre-protein recognition, translocation and sorting across or into it. Mitochondrial protein import machineries also interact transiently with other protein complexes of the respiratory chain or those involved in the maintenance of membrane architecture. Hence mitochondrial protein translocation is an indispensable part of the regulatory network that maintains protein biogenesis, bioenergetics, membrane dynamics and quality control of the organelle. Various stress conditions and diseases that are associated with mitochondrial import defects lead to changes in cellular transcriptomic and proteomic profiles. Dysfunction in mitochondrial protein import also causes over-accumulation of precursor proteins and their aggregation in the cytosol. Multiple pathways may be activated for buffering these harmful consequences. Here, we present a comprehensive picture of import machinery and its role in cellular quality control in response to defective mitochondrial import. We also discuss the pathological consequences of dysfunctional mitochondrial protein import in neurodegeneration and cancer.
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Affiliation(s)
- Sebabrata Maity
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, 700064, India.,Homi Bhabha National Institute, India
| | - Oishee Chakrabarti
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, 700064, India.,Homi Bhabha National Institute, India
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16
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Lerner E, Barth A, Hendrix J, Ambrose B, Birkedal V, Blanchard SC, Börner R, Sung Chung H, Cordes T, Craggs TD, Deniz AA, Diao J, Fei J, Gonzalez RL, Gopich IV, Ha T, Hanke CA, Haran G, Hatzakis NS, Hohng S, Hong SC, Hugel T, Ingargiola A, Joo C, Kapanidis AN, Kim HD, Laurence T, Lee NK, Lee TH, Lemke EA, Margeat E, Michaelis J, Michalet X, Myong S, Nettels D, Peulen TO, Ploetz E, Razvag Y, Robb NC, Schuler B, Soleimaninejad H, Tang C, Vafabakhsh R, Lamb DC, Seidel CAM, Weiss S. FRET-based dynamic structural biology: Challenges, perspectives and an appeal for open-science practices. eLife 2021; 10:e60416. [PMID: 33779550 PMCID: PMC8007216 DOI: 10.7554/elife.60416] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 02/09/2021] [Indexed: 12/18/2022] Open
Abstract
Single-molecule FRET (smFRET) has become a mainstream technique for studying biomolecular structural dynamics. The rapid and wide adoption of smFRET experiments by an ever-increasing number of groups has generated significant progress in sample preparation, measurement procedures, data analysis, algorithms and documentation. Several labs that employ smFRET approaches have joined forces to inform the smFRET community about streamlining how to perform experiments and analyze results for obtaining quantitative information on biomolecular structure and dynamics. The recent efforts include blind tests to assess the accuracy and the precision of smFRET experiments among different labs using various procedures. These multi-lab studies have led to the development of smFRET procedures and documentation, which are important when submitting entries into the archiving system for integrative structure models, PDB-Dev. This position paper describes the current 'state of the art' from different perspectives, points to unresolved methodological issues for quantitative structural studies, provides a set of 'soft recommendations' about which an emerging consensus exists, and lists openly available resources for newcomers and seasoned practitioners. To make further progress, we strongly encourage 'open science' practices.
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Affiliation(s)
- Eitan Lerner
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, and The Center for Nanoscience and Nanotechnology, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of JerusalemJerusalemIsrael
| | - Anders Barth
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Jelle Hendrix
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre and Biomedical Research Institute (BIOMED), Hasselt UniversityDiepenbeekBelgium
| | - Benjamin Ambrose
- Department of Chemistry, University of SheffieldSheffieldUnited Kingdom
| | - Victoria Birkedal
- Department of Chemistry and iNANO center, Aarhus UniversityAarhusDenmark
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research HospitalMemphisUnited States
| | - Richard Börner
- Laserinstitut HS Mittweida, University of Applied Science MittweidaMittweidaGermany
| | - Hoi Sung Chung
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität MünchenPlanegg-MartinsriedGermany
| | - Timothy D Craggs
- Department of Chemistry, University of SheffieldSheffieldUnited Kingdom
| | - Ashok A Deniz
- Department of Integrative Structural and Computational Biology, The Scripps Research InstituteLa JollaUnited States
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati School of MedicineCincinnatiUnited States
| | - Jingyi Fei
- Department of Biochemistry and Molecular Biology and The Institute for Biophysical Dynamics, University of ChicagoChicagoUnited States
| | - Ruben L Gonzalez
- Department of Chemistry, Columbia UniversityNew YorkUnited States
| | - Irina V Gopich
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Howard Hughes Medical InstituteBaltimoreUnited States
| | - Christian A Hanke
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of ScienceRehovotIsrael
| | - Nikos S Hatzakis
- Department of Chemistry & Nanoscience Centre, University of CopenhagenCopenhagenDenmark
- Denmark Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of CopenhagenCopenhagenDenmark
| | - Sungchul Hohng
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National UniversitySeoulRepublic of Korea
| | - Seok-Cheol Hong
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science and Department of Physics, Korea UniversitySeoulRepublic of Korea
| | - Thorsten Hugel
- Institute of Physical Chemistry and Signalling Research Centres BIOSS and CIBSS, University of FreiburgFreiburgGermany
| | - Antonino Ingargiola
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
| | - Chirlmin Joo
- Department of BioNanoScience, Kavli Institute of Nanoscience, Delft University of TechnologyDelftNetherlands
| | - Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of OxfordOxfordUnited Kingdom
| | - Harold D Kim
- School of Physics, Georgia Institute of TechnologyAtlantaUnited States
| | - Ted Laurence
- Physical and Life Sciences Directorate, Lawrence Livermore National LaboratoryLivermoreUnited States
| | - Nam Ki Lee
- School of Chemistry, Seoul National UniversitySeoulRepublic of Korea
| | - Tae-Hee Lee
- Department of Chemistry, Pennsylvania State UniversityUniversity ParkUnited States
| | - Edward A Lemke
- Departments of Biology and Chemistry, Johannes Gutenberg UniversityMainzGermany
- Institute of Molecular Biology (IMB)MainzGermany
| | - Emmanuel Margeat
- Centre de Biologie Structurale (CBS), CNRS, INSERM, Universitié de MontpellierMontpellierFrance
| | | | - Xavier Michalet
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
| | - Sua Myong
- Department of Biophysics, Johns Hopkins UniversityBaltimoreUnited States
| | - Daniel Nettels
- Department of Biochemistry and Department of Physics, University of ZurichZurichSwitzerland
| | - Thomas-Otavio Peulen
- Department of Bioengineering and Therapeutic Sciences, University of California, San FranciscoSan FranciscoUnited States
| | - Evelyn Ploetz
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-UniversitätMünchenGermany
| | - Yair Razvag
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, and The Center for Nanoscience and Nanotechnology, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of JerusalemJerusalemIsrael
| | - Nicole C Robb
- Warwick Medical School, University of WarwickCoventryUnited Kingdom
| | - Benjamin Schuler
- Department of Biochemistry and Department of Physics, University of ZurichZurichSwitzerland
| | - Hamid Soleimaninejad
- Biological Optical Microscopy Platform (BOMP), University of MelbourneParkvilleAustralia
| | - Chun Tang
- College of Chemistry and Molecular Engineering, PKU-Tsinghua Center for Life Sciences, Beijing National Laboratory for Molecular Sciences, Peking UniversityBeijingChina
| | - Reza Vafabakhsh
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Don C Lamb
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-UniversitätMünchenGermany
| | - Claus AM Seidel
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Shimon Weiss
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
- Department of Physiology, CaliforniaNanoSystems Institute, University of California, Los AngelesLos AngelesUnited States
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17
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Cho H, Shim WJ, Liu Y, Shan SO. J-domain proteins promote client relay from Hsp70 during tail-anchored membrane protein targeting. J Biol Chem 2021; 296:100546. [PMID: 33741343 PMCID: PMC8054193 DOI: 10.1016/j.jbc.2021.100546] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/22/2021] [Accepted: 03/15/2021] [Indexed: 01/17/2023] Open
Abstract
J-domain proteins (JDPs) play essential roles in Hsp70 function by assisting Hsp70 in client trapping and regulating the Hsp70 ATPase cycle. Here, we report that JDPs can further enhance the targeting competence of Hsp70-bound client proteins during tail-anchored protein (TA) biogenesis. In the guided-entry-of-tail-anchored protein pathway in yeast, nascent TAs are captured by cytosolic Hsp70 and sequentially relayed to downstream chaperones, Sgt2 and Get3, for delivery to the ER. We found that two JDPs, Ydj1 and Sis1, function in parallel to support TA targeting to the ER in vivo. Biochemical analyses showed that, while Ydj1 and Sis1 differ in their ability to assist Hsp70 in TA trapping, both JDPs enhance the transfer of Hsp70-bound TAs to Sgt2. The ability of the JDPs to regulate the ATPase cycle of Hsp70 is essential for enhancing the transfer competence of Hsp70-bound TAs in vitro and for supporting TA insertion in vivo. These results demonstrate a role of JDPs in regulating the conformation of Hsp70-bound clients during membrane protein biogenesis.
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Affiliation(s)
- Hyunju Cho
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Woo Jun Shim
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Yumeng Liu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA.
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18
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Zhou H, Ren J, Toan S, Mui D. Role of mitochondrial quality surveillance in myocardial infarction: From bench to bedside. Ageing Res Rev 2021; 66:101250. [PMID: 33388396 DOI: 10.1016/j.arr.2020.101250] [Citation(s) in RCA: 135] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/10/2020] [Accepted: 12/22/2020] [Indexed: 12/17/2022]
Abstract
Myocardial infarction (MI) is the irreversible death of cardiomyocyte secondary to prolonged lack of oxygen or fresh blood supply. Historically considered as merely cardiomyocyte powerhouse that manufactures ATP and other metabolites, mitochondrion is recently being identified as a signal regulator that is implicated in the crosstalk and signal integration of cardiomyocyte contraction, metabolism, inflammation, and death. Mitochondria quality surveillance is an integrated network system modifying mitochondrial structure and function through the coordination of various processes including mitochondrial fission, fusion, biogenesis, bioenergetics, proteostasis, and degradation via mitophagy. Mitochondrial fission favors the elimination of depolarized mitochondria through mitophagy, whereas mitochondrial fusion preserves the mitochondrial network upon stress through integration of two or more small mitochondria into an interconnected phenotype. Mitochondrial biogenesis represents a regenerative program to replace old and damaged mitochondria with new and healthy ones. Mitochondrial bioenergetics is regulated by a metabolic switch between glucose and fatty acid usage, depending on oxygen availability. To maintain the diversity and function of mitochondrial proteins, a specialized protein quality control machinery regulates protein dynamics and function through the activity of chaperones and proteases, and induction of the mitochondrial unfolded protein response. In this review, we provide an overview of the molecular mechanisms governing mitochondrial quality surveillance and highlight the most recent preclinical and clinical therapeutic approaches to restore mitochondrial fitness during both MI and post-MI heart failure.
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Affiliation(s)
- Hao Zhou
- Department of Cardiology, Chinese PLA General Hospital, Medical School of Chinese PLA, Beijing 100853, China.
| | - Jun Ren
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071, USA
| | - Sam Toan
- Department of Chemical Engineering, University of Minnesota-Duluth, Duluth, MN 55812, USA
| | - David Mui
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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19
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LONP1 and mtHSP70 cooperate to promote mitochondrial protein folding. Nat Commun 2021; 12:265. [PMID: 33431889 PMCID: PMC7801493 DOI: 10.1038/s41467-020-20597-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 12/10/2020] [Indexed: 01/23/2023] Open
Abstract
Most mitochondrial precursor polypeptides are imported from the cytosol into the mitochondrion, where they must efficiently undergo folding. Mitochondrial precursors are imported as unfolded polypeptides. For proteins of the mitochondrial matrix and inner membrane, two separate chaperone systems, HSP60 and mitochondrial HSP70 (mtHSP70), facilitate protein folding. We show that LONP1, an AAA+ protease of the mitochondrial matrix, works with the mtHSP70 chaperone system to promote mitochondrial protein folding. Inhibition of LONP1 results in aggregation of a protein subset similar to that caused by knockdown of DNAJA3, a co-chaperone of mtHSP70. LONP1 is required for DNAJA3 and mtHSP70 solubility, and its ATPase, but not its protease activity, is required for this function. In vitro, LONP1 shows an intrinsic chaperone-like activity and collaborates with mtHSP70 to stabilize a folding intermediate of OXA1L. Our results identify LONP1 as a critical factor in the mtHSP70 folding pathway and demonstrate its proposed chaperone activity. Most mitochondrial proteins are imported from the cytosol and must fold in the mitochondria. Here, the authors show that the mitochondrial protease LONP1 plays a critical role in the mtHSP70 chaperone system independently of its protease activity.
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20
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General anesthesia activates the mitochondrial unfolded protein response and induces age-dependent, long-lasting changes in mitochondrial function in the developing brain. Neurotoxicology 2020; 82:1-8. [PMID: 33144179 DOI: 10.1016/j.neuro.2020.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 10/13/2020] [Accepted: 10/27/2020] [Indexed: 11/22/2022]
Abstract
General anesthesia induces changes in dendritic spine number and synaptic transmission in developing mice. These changes are rather disturbing, as similar changes are seen in animal models of neurodevelopmental disorders. We previously suggested that mTor-dependent upregulation of mitochondrial function may be involved in such changes. To further understand the significance of mitochondrial changes after general anesthesia during neurodevelopment, we exposed young mice to 2.5 % sevoflurane for 2 h followed by injection of rotenone, a mitochondrial complex I inhibitor. In postnatal day 17 (PND17) mice, intraperitoneal injection of rotenone not only blocked sevoflurane-induced increases in mitochondrial function, it also prevented sevoflurane-induced changes in excitatory synaptic transmission. Interestingly, similar changes were not observed in younger, neonatal mice (PND7). We next assessed whether the mitochondrial unfolded protein response (UPRmt) acted as a link between anesthetic exposure and mitochondrial function. Expression of UPRmt proteins, which help maintain protein-folding homeostasis and increase mitochondrial function, was increased 6 h after sevoflurane exposure. Our results show that a single, brief sevoflurane exposure induces age-dependent changes in mitochondrial function that constitute an important mechanism for the increase in excitatory synaptic transmission in late postnatal mice, and also suggest mitochondria and UPRmt as potential targets for preventing anesthesia toxicity.
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21
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Urbina-Varela R, Castillo N, Videla LA, del Campo A. Impact of Mitophagy and Mitochondrial Unfolded Protein Response as New Adaptive Mechanisms Underlying Old Pathologies: Sarcopenia and Non-Alcoholic Fatty Liver Disease. Int J Mol Sci 2020; 21:E7704. [PMID: 33081022 PMCID: PMC7589512 DOI: 10.3390/ijms21207704] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondria are the first-line defense of the cell in the presence of stressing processes that can induce mitochondrial dysfunction. Under these conditions, the activation of two axes is accomplished, namely, (i) the mitochondrial unfolded protein response (UPRmt) to promote cell recovery and survival of the mitochondrial network; (ii) the mitophagy process to eliminate altered or dysfunctional mitochondria. For these purposes, the former response induces the expression of chaperones, proteases, antioxidant components and protein import and assembly factors, whereas the latter is signaled through the activation of the PINK1/Parkin and BNIP3/NIX pathways. These adaptive mechanisms may be compromised during aging, leading to the development of several pathologies including sarcopenia, defined as the loss of skeletal muscle mass and performance; and non-alcoholic fatty liver disease (NAFLD). These age-associated diseases are characterized by the progressive loss of organ function due to the accumulation of reactive oxygen species (ROS)-induced damage to biomolecules, since the ability to counteract the continuous and large generation of ROS becomes increasingly inefficient with aging, resulting in mitochondrial dysfunction as a central pathogenic mechanism. Nevertheless, the role of the integrated stress response (ISR) involving UPRmt and mitophagy in the development and progression of these illnesses is still a matter of debate, considering that some studies indicate that the prolonged exposure to low levels of stress may trigger these mechanisms to maintain mitohormesis, whereas others sustain that chronic activation of them could lead to cell death. In this review, we discuss the available research that contributes to unveil the role of the mitochondrial UPR in the development of sarcopenia, in an attempt to describe changes prior to the manifestation of severe symptoms; and in NAFLD, in order to prevent or reverse fat accumulation and its progression by means of suitable protocols to be addressed in future studies.
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Affiliation(s)
- Rodrigo Urbina-Varela
- Laboratorio de Fisiología y Bioenergética Celular, Departamento de Farmacia, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7810000, Chile; (R.U.-V.); (N.C.)
| | - Nataly Castillo
- Laboratorio de Fisiología y Bioenergética Celular, Departamento de Farmacia, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7810000, Chile; (R.U.-V.); (N.C.)
| | - Luis A. Videla
- Molecular and Clinical Pharmacology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago 8380453, Chile;
| | - Andrea del Campo
- Laboratorio de Fisiología y Bioenergética Celular, Departamento de Farmacia, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7810000, Chile; (R.U.-V.); (N.C.)
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22
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Tomiczek B, Delewski W, Nierzwicki L, Stolarska M, Grochowina I, Schilke B, Dutkiewicz R, Uzarska MA, Ciesielski SJ, Czub J, Craig EA, Marszalek J. Two-step mechanism of J-domain action in driving Hsp70 function. PLoS Comput Biol 2020; 16:e1007913. [PMID: 32479549 PMCID: PMC7289447 DOI: 10.1371/journal.pcbi.1007913] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 06/11/2020] [Accepted: 04/28/2020] [Indexed: 12/02/2022] Open
Abstract
J-domain proteins (JDPs), obligatory Hsp70 cochaperones, play critical roles in protein homeostasis. They promote key allosteric transitions that stabilize Hsp70 interaction with substrate polypeptides upon hydrolysis of its bound ATP. Although a recent crystal structure revealed the physical mode of interaction between a J-domain and an Hsp70, the structural and dynamic consequences of J-domain action once bound and how Hsp70s discriminate among its multiple JDP partners remain enigmatic. We combined free energy simulations, biochemical assays and evolutionary analyses to address these issues. Our results indicate that the invariant aspartate of the J-domain perturbs a conserved intramolecular Hsp70 network of contacts that crosses domains. This perturbation leads to destabilization of the domain-domain interface—thereby promoting the allosteric transition that triggers ATP hydrolysis. While this mechanistic step is driven by conserved residues, evolutionarily variable residues are key to initial JDP/Hsp70 recognition—via electrostatic interactions between oppositely charged surfaces. We speculate that these variable residues allow an Hsp70 to discriminate amongst JDP partners, as many of them have coevolved. Together, our data points to a two-step mode of J-domain action, a recognition stage followed by a mechanistic stage. It is well appreciated that Hsp70-based systems are the most versatile among molecular chaperones—functioning in all cell types and in all subcellular compartments. Via cyclic binding to protein substrates, Hsp70s facilitate their folding, trafficking, degradation and ability to interact with other proteins. Hsp70 function, however, depends on transient interaction with J-domain protein cochaperones that not only deliver substrates, but also activate the structural changes needed for efficient Hsp70 binding to substrate. But how J-domain proteins mechanistically function to drive these changes and how an Hsp70 discriminates among multiple J-domain partners have remained challenging central questions. Here, by using a combination of computational, evolutionary and experimental approaches, we provide evidence for a two-step mechanism. The initial recognition step involves variable residues that allow fine tuning of both the specificity and strength of J-domain protein interaction with Hsp70. The second, that is the mechanistic step, involves conserved residues that act to disrupt a conserved network of intramolecular interactions within Hsp70, thus ensuring robust activation of the structural changes necessary for effective substrate binding. We suggest that our findings are likely applicable to most Hsp70 systems.
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Affiliation(s)
- Bartlomiej Tomiczek
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Wojciech Delewski
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Lukasz Nierzwicki
- Department of Physical Chemistry, Gdansk University of Technology, Gdansk, Poland
| | - Milena Stolarska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Igor Grochowina
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Brenda Schilke
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Rafal Dutkiewicz
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Marta A. Uzarska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Szymon J. Ciesielski
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jacek Czub
- Department of Physical Chemistry, Gdansk University of Technology, Gdansk, Poland
- * E-mail: (JC); (EAC); (JM)
| | - Elizabeth A. Craig
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (JC); (EAC); (JM)
| | - Jaroslaw Marszalek
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (JC); (EAC); (JM)
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Dalphin MD, Stangl AJ, Liu Y, Cavagnero S. KLR-70: A Novel Cationic Inhibitor of the Bacterial Hsp70 Chaperone. Biochemistry 2020; 59:1946-1960. [PMID: 32326704 DOI: 10.1021/acs.biochem.0c00320] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The heat-shock factor Hsp70 and other molecular chaperones play a central role in nascent protein folding. Elucidating the task performed by individual chaperones within the complex cellular milieu, however, has been challenging. One strategy for addressing this goal has been to monitor protein biogenesis in the absence and presence of inhibitors of a specific chaperone, followed by analysis of folding outcomes under both conditions. In this way, the role of the chaperone of interest can be discerned. However, development of chaperone inhibitors, including well-known proline-rich antimicrobial peptides, has been fraught with undesirable side effects, including decreased protein expression yields. Here, we introduce KLR-70, a rationally designed cationic inhibitor of the Escherichia coli Hsp70 chaperone (also known as DnaK). KLR-70 is a 14-amino acid peptide bearing naturally occurring residues and engineered to interact with the DnaK substrate-binding domain. The interaction of KLR-70 with DnaK is enantioselective and is characterized by high affinity in a buffered solution. Importantly, KLR-70 does not significantly interact with the DnaJ and GroEL/ES chaperones, and it does not alter nascent protein biosynthesis yields across a wide concentration range. Some attenuation of the anti-DnaK activity of KLR-70, however, has been observed in the complex E. coli cell-free environment. Interestingly, the d enantiomer D-KLR-70, unlike its all-L KLR-70 counterpart, does not bind the DnaK and DnaJ chaperones, yet it strongly inhibits translation. This outcome suggests that the two enantiomers (KLR-70 and D-KLR-70) may serve as orthogonal inhibitors of chaperone binding and translation. In summary, KLR-70 is a novel chaperone inhibitor with high affinity and selectivity for bacterial Hsp70 and with considerable potential to help in parsing out the role of Hsp70 in nascent protein folding.
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Affiliation(s)
- Matthew D Dalphin
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Andrew J Stangl
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Yue Liu
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Silvia Cavagnero
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
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24
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How to get to the other side of the mitochondrial inner membrane – the protein import motor. Biol Chem 2020; 401:723-736. [DOI: 10.1515/hsz-2020-0106] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 02/25/2020] [Indexed: 12/13/2022]
Abstract
AbstractBiogenesis of mitochondria relies on import of more than 1000 different proteins from the cytosol. Approximately 70% of these proteins follow the presequence pathway – they are synthesized with cleavable N-terminal extensions called presequences and reach the final place of their function within the organelle with the help of the TOM and TIM23 complexes in the outer and inner membranes, respectively. The translocation of proteins along the presequence pathway is powered by the import motor of the TIM23 complex. The import motor of the TIM23 complex is localized at the matrix face of the inner membrane and is likely the most complicated Hsp70-based system identified to date. How it converts the energy of ATP hydrolysis into unidirectional translocation of proteins into mitochondria remains one of the biggest mysteries of this translocation pathway. Here, the knowns and the unknowns of the mitochondrial protein import motor are discussed.
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25
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Sharma S, Saini R, Sharma P, Saini A, Nehru B. Maintenance of Amyloid-beta Homeostasis by Carbenoxolone Post Aβ-42 Oligomer Injection in Rat Brain. Neuroscience 2020; 431:86-102. [DOI: 10.1016/j.neuroscience.2020.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 10/25/2022]
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26
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Kinetics of the conformational cycle of Hsp70 reveals the importance of the dynamic and heterogeneous nature of Hsp70 for its function. Proc Natl Acad Sci U S A 2020; 117:7814-7823. [PMID: 32198203 PMCID: PMC7148561 DOI: 10.1073/pnas.1914376117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Heat shock protein 70 kDa (Hsp70) plays a central role in maintaining protein homeostasis. It cooperates with cochaperone Hsp40, which stimulates Hsp70 ATPase activity and presents protein substrates to Hsp70 to assist refolding. The mechanism by which Hsp40 regulates the intramolecular and intermolecular changes of Hsp70 is still largely unknown. Here, by bulk and single-molecule FRET, we report the conformational dynamics of Hsp70 and its regulation by Hsp40 as well as the kinetics of the multistep Hsp70–Hsp40 functional cycle. We show that Hsp40 modulates the conformations of ATP-bound Hsp70 to a domain-undocked ATPase-stimulated state, and facilitates the formation of a heterotetrameric Hsp70–Hsp40 complex. Our findings provide insights into the functional mechanism of this core chaperone machinery. Hsp70 is a conserved molecular chaperone that plays an indispensable role in regulating protein folding, translocation, and degradation. The conformational dynamics of Hsp70 and its regulation by cochaperones are vital to its function. Using bulk and single-molecule fluorescence resonance energy transfer (smFRET) techniques, we studied the interdomain conformational distribution of human stress-inducible Hsp70A1 and the kinetics of conformational changes induced by nucleotide and the Hsp40 cochaperone Hdj1. We found that the conformations between and within the nucleotide- and substrate-binding domains show heterogeneity. The conformational distribution in the ATP-bound state can be induced by Hdj1 to form an “ADP-like” undocked conformation, which is an ATPase-stimulated state. Kinetic measurements indicate that Hdj1 binds to monomeric Hsp70 as the first step, then induces undocking of the two domains and closing of the substrate-binding cleft. Dimeric Hdj1 then facilitates dimerization of Hsp70 and formation of a heterotetrameric Hsp70–Hsp40 complex. Our results provide a kinetic view of the conformational cycle of Hsp70 and reveal the importance of the dynamic nature of Hsp70 for its function.
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27
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Pandey M, Nabi J, Tabassum N, Pottoo FH, Khatik R, Ahmad N. Molecular Chaperones in Neurodegeneration. QUALITY CONTROL OF CELLULAR PROTEIN IN NEURODEGENERATIVE DISORDERS 2020. [DOI: 10.4018/978-1-7998-1317-0.ch014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cellular chaperones are essential players to this protein quality control network that functions to prevent protein misfolding, refold misfolded proteins, or degrade them, thereby maintaining neuronal proteostasis. Moreover, overexpression of cellular chaperones is considered to inhibit protein aggregation and apoptosis in various experimental models of neurodegeneration. Alterations or downregulation of chaperone machinery by age-related decline, molecular crowding, or genetic mutations are regarded as key pathological hallmarks of neurodegenerative disorders like Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), and Prion diseases. Therefore, chaperones may serve as potential therapeutic targets in these diseases. This chapter presents a generalized view of misfolding and aggregation of proteins in neurodegeneration and then critically analyses some of the known cellular chaperones and their role in several neurodegenerative disorders.
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Affiliation(s)
- Mukesh Pandey
- Department of Pharmaceutics, Delhi Institute of Pharmaceutical Sciences and Research, India
| | - Jahangir Nabi
- Department of Pharmaceutical Sciences (Pharmacology Division), Faculty of Applied Sciences and Technology, University of Kashmir, Srinagar, India
| | - Nahida Tabassum
- Department of Pharmaceutical Sciences (Pharmacology Division), Faculty of Applied Sciences and Technology, University of Kashmir, Srinagar, India
| | - Faheem Hyder Pottoo
- Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, Saudi Arabia
| | - Renuka Khatik
- Hefei National Laboratory of Physical Sciences at the Microscale, University of Science and Technology of China, China
| | - Niyaz Ahmad
- Department of Pharmaceutics, College of Clinical Pharmacy, Imam Abdul Rahman Bin Faisal University, Saudi Arabia
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28
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Li H, Zhu H, Sarbeng EB, Liu Q, Tian X, Yang Y, Lyons C, Zhou L, Liu Q. An unexpected second binding site for polypeptide substrates is essential for Hsp70 chaperone activity. J Biol Chem 2019; 295:584-596. [PMID: 31806707 DOI: 10.1074/jbc.ra119.009686] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 12/02/2019] [Indexed: 12/14/2022] Open
Abstract
Heat shock proteins of 70 kDa (Hsp70s) are ubiquitous and highly conserved molecular chaperones. They play multiple essential roles in assisting with protein folding and maintaining protein homeostasis. Their chaperone activity has been proposed to require several rounds of binding to and release of polypeptide substrates at the substrate-binding domain (SBD) of Hsp70s. All available structures have revealed a single substrate-binding site in the SBD that binds a single segment of an extended polypeptide of 3-4 residues. However, this well-established single peptide-binding site alone has made it difficult to explain the efficient chaperone activity of Hsp70s. In this study, using purified proteins and site-directed mutagenesis, along with fluorescence polarization and luciferase-refolding assays, we report the unexpected discovery of a second peptide-binding site in Hsp70s. More importantly, the biochemical analyses suggested that this novel binding site, named here P2, is essential for Hsp70 chaperone activity. Furthermore, cross-linking and mutagenesis studies indicated that this second binding site is in the SBD adjacent to the first binding site. Taken together, our results suggest that these two essential binding sites of Hsp70s cooperate in protein folding.
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Affiliation(s)
- Hongtao Li
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Huanyu Zhu
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Evans Boateng Sarbeng
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Qingdai Liu
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Xueli Tian
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Ying Yang
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Charles Lyons
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Lei Zhou
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Qinglian Liu
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298.
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29
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Heiss G, Ploetz E, Voith von Voithenberg L, Viswanathan R, Glaser S, Schluesche P, Madhira S, Meisterernst M, Auble DT, Lamb DC. Conformational changes and catalytic inefficiency associated with Mot1-mediated TBP-DNA dissociation. Nucleic Acids Res 2019; 47:2793-2806. [PMID: 30649478 PMCID: PMC6451094 DOI: 10.1093/nar/gky1322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 12/21/2018] [Accepted: 01/07/2019] [Indexed: 11/12/2022] Open
Abstract
The TATA-box Binding Protein (TBP) plays a central role in regulating gene expression and is the first step in the process of pre-initiation complex (PIC) formation on promoter DNA. The lifetime of TBP at the promoter site is controlled by several cofactors including the Modifier of transcription 1 (Mot1), an essential TBP-associated ATPase. Based on ensemble measurements, Mot1 can use adenosine triphosphate (ATP) hydrolysis to displace TBP from DNA and various models for how this activity is coupled to transcriptional regulation have been proposed. However, the underlying molecular mechanism of Mot1 action is not well understood. In this work, the interaction of Mot1 with the DNA/TBP complex was investigated by single-pair Förster resonance energy transfer (spFRET). Upon Mot1 binding to the DNA/TBP complex, a transition in the DNA/TBP conformation was observed. Hydrolysis of ATP by Mot1 led to a conformational change but was not sufficient to efficiently disrupt the complex. SpFRET measurements of dual-labeled DNA suggest that Mot1's ATPase activity primes incorrectly oriented TBP for dissociation from DNA and additional Mot1 in solution is necessary for TBP unbinding. These findings provide a framework for understanding how the efficiency of Mot1's catalytic activity is tuned to establish a dynamic pool of TBP without interfering with stable and functional TBP-containing complexes.
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Affiliation(s)
- Gregor Heiss
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Evelyn Ploetz
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Lena Voith von Voithenberg
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Ramya Viswanathan
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Samson Glaser
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Peter Schluesche
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Sushi Madhira
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
| | - Michael Meisterernst
- Institut für Molekulare Tumorbiologie, Westfälische Wilhelms-Universität, Münster 48149, Germany
| | - David T Auble
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Don C Lamb
- Department für Chemie, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-Universität, München 81377, Germany
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30
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Shan SO. Guiding tail-anchored membrane proteins to the endoplasmic reticulum in a chaperone cascade. J Biol Chem 2019; 294:16577-16586. [PMID: 31575659 PMCID: PMC6851334 DOI: 10.1074/jbc.rev119.006197] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Newly synthesized integral membrane proteins must traverse the aqueous cytosolic environment before arrival at their membrane destination and are prone to aggregation, misfolding, and mislocalization during this process. The biogenesis of integral membrane proteins therefore poses acute challenges to protein homeostasis within a cell and requires the action of effective molecular chaperones. Chaperones that mediate membrane protein targeting not only need to protect the nascent transmembrane domains from improper exposure in the cytosol, but also need to accurately select client proteins and actively guide their clients to the appropriate target membrane. The mechanisms by which cellular chaperones work together to coordinate this complex process are only beginning to be delineated. Here, we summarize recent advances in studies of the tail-anchored membrane protein targeting pathway, which revealed a network of chaperones, cochaperones, and targeting factors that together drive and regulate this essential process. This pathway is emerging as an excellent model system to decipher the mechanism by which molecular chaperones overcome the multiple challenges during post-translational membrane protein biogenesis and to gain insights into the functional organization of multicomponent chaperone networks.
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Affiliation(s)
- Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
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31
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Liu Q, Liang C, Zhou L. Structural and functional analysis of the Hsp70/Hsp40 chaperone system. Protein Sci 2019; 29:378-390. [PMID: 31509306 DOI: 10.1002/pro.3725] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 08/29/2019] [Accepted: 09/03/2019] [Indexed: 12/22/2022]
Abstract
As one of the most abundant and highly conserved molecular chaperones, the 70-kDa heat shock proteins (Hsp70s) play a key role in maintaining cellular protein homeostasis (proteostasis), one of the most fundamental tasks for every living organism. In this role, Hsp70s are inextricably linked to many human diseases, most notably cancers and neurodegenerative diseases, and are increasingly recognized as important drug targets for developing novel therapeutics for these diseases. Hsp40s are a class of essential and universal partners for Hsp70s in almost all aspects of proteostasis. Thus, Hsp70s and Hsp40s together constitute one of the most important chaperone systems across all kingdoms of life. In recent years, we have witnessed significant progress in understanding the molecular mechanism of this chaperone system through structural and functional analysis. This review will focus on this recent progress, mainly from a structural perspective.
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Affiliation(s)
- Qinglian Liu
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia
| | - Ce Liang
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia
| | - Lei Zhou
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia
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32
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Krainer G, Keller S, Schlierf M. Structural dynamics of membrane-protein folding from single-molecule FRET. Curr Opin Struct Biol 2019; 58:124-137. [DOI: 10.1016/j.sbi.2019.05.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 05/27/2019] [Indexed: 12/15/2022]
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33
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Kumar V, Peter JJ, Sagar A, Ray A, Jha MP, Rebeaud ME, Tiwari S, Goloubinoff P, Ashish F, Mapa K. Interdomain communication suppressing high intrinsic ATPase activity of Sse1 is essential for its co-disaggregase activity with Ssa1. FEBS J 2019; 287:671-694. [PMID: 31423733 DOI: 10.1111/febs.15045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 07/08/2019] [Accepted: 08/16/2019] [Indexed: 01/19/2023]
Abstract
In eukaryotes, Hsp110s are unambiguous cognates of the Hsp70 chaperones, in primary sequence, domain organization, and structure. Hsp110s function as nucleotide exchange factors (NEFs) for the Hsp70s although their apparent loss of Hsp70-like chaperone activity, nature of interdomain communication, and breadth of domain functions are still puzzling. Here, by combining single-molecule FRET, small angle X-ray scattering measurements (SAXS), and MD simulation, we show that yeast Hsp110, Sse1 lacks canonical Hsp70-like interdomain allostery. However, the protein exhibits unique noncanonical conformational changes within its domains. Sse1 maintains an open-lid substrate-binding domain (SBD) in close contact with its nucleotide-binding domain (NBD), irrespective of its ATP hydrolysis status. To further appreciate such ATP-hydrolysis-independent exhaustive interaction between two domains of Hsp110s, NBD-SBD chimera was constructed between Hsp110 (Sse1) and Hsp70 (Ssa1). In Sse1/Ssa1 chimera, we observed undocking of two domains leading to complete loss of NEF activity of Sse1. Interestingly, chimeric proteins exhibited significantly enhanced ATPase rate of Sse1-NBD compared to wild-type protein, implying that intrinsic ATPase activity of the protein remains mostly repressed. Apart from repressing the high ATPase activity of its NBD, interactions between two domains confer thermal stability to Sse1 and play critical role in the (co)chaperoning function of Sse1 in Ssa1-mediated disaggregation activity. Altogether, Sse1 exhibits a unique interdomain interaction, which is essential for its NEF activity, suppression of high intrinsic ATPase activity, co-chaperoning activity in disaggregase machinery, and stability of the protein.
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Affiliation(s)
- Vignesh Kumar
- Proteomics and Structural Biology Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India.,Academy of Scientific and Innovative Research (AcSir), CSIR-HRDC, Ghaziabad, India
| | - Joshua Jebakumar Peter
- Proteomics and Structural Biology Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Amin Sagar
- CSIR-Institute of Microbial Technology, Chandigarh, Uttar Pradesh, India
| | - Arjun Ray
- Proteomics and Structural Biology Unit, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India.,Academy of Scientific and Innovative Research (AcSir), CSIR-HRDC, Ghaziabad, India
| | - Mainak Pratim Jha
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Greater Noida, India
| | - Mathieu E Rebeaud
- Department of Plant Molecular Biology, University of Lausanne, Switzerland
| | - Satyam Tiwari
- Department of Plant Molecular Biology, University of Lausanne, Switzerland
| | - Pierre Goloubinoff
- Department of Plant Molecular Biology, University of Lausanne, Switzerland
| | - Fnu Ashish
- CSIR-Institute of Microbial Technology, Chandigarh, Uttar Pradesh, India
| | - Koyeli Mapa
- Academy of Scientific and Innovative Research (AcSir), CSIR-HRDC, Ghaziabad, India.,Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Greater Noida, India
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34
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Mandal A, Drerup CM. Axonal Transport and Mitochondrial Function in Neurons. Front Cell Neurosci 2019; 13:373. [PMID: 31447650 PMCID: PMC6696875 DOI: 10.3389/fncel.2019.00373] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/30/2019] [Indexed: 12/31/2022] Open
Abstract
The complex and elaborate architecture of a neuron poses a great challenge to the cellular machinery which localizes proteins and organelles, such as mitochondria, to necessary locations. Proper mitochondrial localization in neurons is particularly important as this organelle provides energy and metabolites essential to form and maintain functional neural connections. Consequently, maintenance of a healthy pool of mitochondria and removal of damaged organelles are essential for neuronal homeostasis. Long distance transport of the organelle itself as well as components necessary for maintaining mitochondria in distal compartments are important for a constant supply of healthy mitochondria at the right time and place. Accordingly, many neurodegenerative diseases have been associated with mitochondrial abnormalities. Here, we review our current understanding on transport-dependent mechanisms that regulate mitochondrial replenishment. We focus on axonal transport and import of mRNAs and proteins destined for mitochondria as well as mitochondrial fusion and fission to maintain mitochondrial homeostasis in distal compartments of the neuron.
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Affiliation(s)
- Amrita Mandal
- Unit on Neuronal Cell Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Catherine M Drerup
- Unit on Neuronal Cell Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
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35
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Hsp70 molecular chaperones: multifunctional allosteric holding and unfolding machines. Biochem J 2019; 476:1653-1677. [PMID: 31201219 DOI: 10.1042/bcj20170380] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 12/20/2022]
Abstract
The Hsp70 family of chaperones works with its co-chaperones, the nucleotide exchange factors and J-domain proteins, to facilitate a multitude of cellular functions. Central players in protein homeostasis, these jacks-of-many-trades are utilized in a variety of ways because of their ability to bind with selective promiscuity to regions of their client proteins that are exposed when the client is unfolded, either fully or partially, or visits a conformational state that exposes the binding region in a regulated manner. The key to Hsp70 functions is that their substrate binding is transient and allosterically cycles in a nucleotide-dependent fashion between high- and low-affinity states. In the past few years, structural insights into the molecular mechanism of this allosterically regulated binding have emerged and provided deep insight into the deceptively simple Hsp70 molecular machine that is so widely harnessed by nature for diverse cellular functions. In this review, these structural insights are discussed to give a picture of the current understanding of how Hsp70 chaperones work.
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36
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Signaling and Regulation of the Mitochondrial Unfolded Protein Response. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033944. [PMID: 30617048 DOI: 10.1101/cshperspect.a033944] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The mitochondrial proteome encompasses more than a thousand proteins, which are encoded by the mitochondrial and nuclear genomes. Mitochondrial biogenesis and network health relies on maintenance of protein import pathways and the protein-folding environment. Cell-extrinsic or -intrinsic stressors that challenge mitochondrial proteostasis negatively affect organellar function. During conditions of stress, cells use impaired protein import as a sensor for mitochondrial dysfunction to activate a stress response called the mitochondrial unfolded protein response (UPRmt). UPRmt activation leads to an adaptive transcriptional program that promotes mitochondrial recovery, metabolic adaptations, and innate immunity. In this review, we discuss the regulation of UPRmt activation as well as its role in maintaining mitochondrial homeostasis in physiological and pathological scenarios.
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37
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Moseng MA, Nix JC, Page RC. Biophysical Consequences of EVEN-PLUS Syndrome Mutations for the Function of Mortalin. J Phys Chem B 2019; 123:3383-3396. [PMID: 30933555 DOI: 10.1021/acs.jpcb.9b00071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
HSPA9, the gene coding for the mitochondrial chaperone mortalin, is involved in various cellular roles such as mitochondrial protein import, folding, degradation, Fe-S cluster biogenesis, mitochondrial homeostasis, and regulation of the antiapoptotic protein p53. Mutations in the HSPA9 gene, particularly within the region coding for the nucleotide-binding domain (NBD), cause the autosomal disorder known as EVEN-PLUS syndrome. The resulting mutants R126W and Y128C are located on the surface of the mortalin-NBD near the binding interface with the interdomain linker (IDL). We used differential scanning fluorimetry (DSF), biolayer interferometry, X-ray crystallography, ATP hydrolysis assays, and Rosetta docking simulations to study the structural and functional consequences of the EVEN-PLUS syndrome-associated R126W and Y128C mutations within the mortalin-NBD. These results indicate that the surface mutations R126W and Y128C have far-reaching effects that disrupt ATP hydrolysis, interdomain linker binding, and thermostability and increase the propensity for aggregation. The structural differences observed provide insight into how the conformations of mortalin differ from other heat shock protein 70 (Hsp70) homologues. Combined, our biophysical and structural studies contribute to the understanding of the molecular basis for how disease-associated mortalin mutations affect mortalin functionality and the pathogenesis of EVEN-PLUS syndrome.
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Affiliation(s)
- Mitchell A Moseng
- Department of Chemistry and Biochemistry , Miami University , Oxford , Ohio 45056 , United States
| | - Jay C Nix
- Molecular Biology Consortium, Beamline 4.2.2, Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Richard C Page
- Department of Chemistry and Biochemistry , Miami University , Oxford , Ohio 45056 , United States
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38
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Casanova-Morales N, Quiroga-Roger D, Alfaro-Valdés HM, Alavi Z, Lagos-Espinoza MIA, Zocchi G, Wilson CAM. Mechanical properties of BiP protein determined by nano-rheology. Protein Sci 2019; 27:1418-1426. [PMID: 29696702 DOI: 10.1002/pro.3432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/06/2018] [Accepted: 04/19/2018] [Indexed: 02/01/2023]
Abstract
Immunoglobulin Binding Protein (BiP) is a chaperone and molecular motor belonging to the Hsp70 family, involved in the regulation of important biological processes such as synthesis, folding and translocation of proteins in the Endoplasmic Reticulum. BiP has two highly conserved domains: the N-terminal Nucleotide-Binding Domain (NBD), and the C-terminal Substrate-Binding Domain (SBD), connected by a hydrophobic linker. ATP binds and it is hydrolyzed to ADP in the NBD, and BiP's extended polypeptide substrates bind in the SBD. Like many molecular motors, BiP function depends on both structural and catalytic properties that may contribute to its performance. One novel approach to study the mechanical properties of BiP considers exploring the changes in the viscoelastic behavior upon ligand binding, using a technique called nano-rheology. This technique is essentially a traditional rheology experiment, in which an oscillatory force is directly applied to the protein under study, and the resulting average deformation is measured. Our results show that the folded state of the protein behaves like a viscoelastic material, getting softer when it binds nucleotides- ATP, ADP, and AMP-PNP-, but stiffer when binding HTFPAVL peptide substrate. Also, we observed that peptide binding dramatically increases the affinity for ADP, decreasing it dissociation constant (KD ) around 1000 times, demonstrating allosteric coupling between SBD and NBD domains.
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Affiliation(s)
- Nathalie Casanova-Morales
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, 8380494, Chile
| | - Diego Quiroga-Roger
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, 8380494, Chile
| | - Hilda M Alfaro-Valdés
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, 8380494, Chile
| | - Zahra Alavi
- Department of Physics and Astronomy, University of California - Los Angeles, Los Angeles, California, 90095, US.,Department of Physics, Loyola Marymount University, Los Angeles, California, 90045, US
| | - Miguel I A Lagos-Espinoza
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, 8380494, Chile
| | - Giovanni Zocchi
- Department of Physics and Astronomy, University of California - Los Angeles, Los Angeles, California, 90095, US
| | - Christian A M Wilson
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, 8380494, Chile
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39
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Mitochondrial presequence import: Multiple regulatory knobs fine-tune mitochondrial biogenesis and homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:930-944. [PMID: 30802482 DOI: 10.1016/j.bbamcr.2019.02.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 12/22/2022]
Abstract
Mitochondria are pivotal organelles for cellular signaling and metabolism, and their dysfunction leads to severe cellular stress. About 60-70% of the mitochondrial proteome consists of preproteins synthesized in the cytosol with an amino-terminal cleavable presequence targeting signal. The TIM23 complex transports presequence signals towards the mitochondrial matrix. Ultimately, the mature protein segments are either transported into the matrix or sorted to the inner membrane. To ensure accurate preprotein import into distinct mitochondrial sub-compartments, the TIM23 machinery adopts specific functional conformations and interacts with different partner complexes. Regulatory subunits modulate the translocase dynamics, tailoring the import reaction to the incoming preprotein. The mitochondrial membrane potential and the ATP generated via oxidative phosphorylation are key energy sources in driving the presequence import pathway. Thus, mitochondrial dysfunctions have rapid repercussions on biogenesis. Cellular mechanisms exploit the presequence import pathway to monitor mitochondrial dysfunctions and mount transcriptional and proteostatic responses to restore functionality.
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40
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Dahiya V, Buchner J. Functional principles and regulation of molecular chaperones. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2018; 114:1-60. [PMID: 30635079 DOI: 10.1016/bs.apcsb.2018.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To be able to perform their biological function, a protein needs to be correctly folded into its three dimensional structure. The protein folding process is spontaneous and does not require the input of energy. However, in the crowded cellular environment where there is high risk of inter-molecular interactions that may lead to protein molecules sticking to each other, hence forming aggregates, protein folding is assisted. Cells have evolved robust machinery called molecular chaperones to deal with the protein folding problem and to maintain proteins in their functional state. Molecular chaperones promote efficient folding of newly synthesized proteins, prevent their aggregation and ensure protein homeostasis in cells. There are different classes of molecular chaperones functioning in a complex interplay. In this review, we discuss the principal characteristics of different classes of molecular chaperones, their structure-function relationships, their mode of regulation and their involvement in human disorders.
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Affiliation(s)
- Vinay Dahiya
- Center for Integrated Protein Science Munich CIPSM at the Department Chemie, Technische Universität München, Garching, Germany
| | - Johannes Buchner
- Center for Integrated Protein Science Munich CIPSM at the Department Chemie, Technische Universität München, Garching, Germany.
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41
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Mayer MP, Gierasch LM. Recent advances in the structural and mechanistic aspects of Hsp70 molecular chaperones. J Biol Chem 2018; 294:2085-2097. [PMID: 30455352 DOI: 10.1074/jbc.rev118.002810] [Citation(s) in RCA: 169] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hsp70 chaperones are central hubs of the protein quality control network and collaborate with co-chaperones having a J-domain (an ∼70-residue-long helical hairpin with a flexible loop and a conserved His-Pro-Asp motif required for ATP hydrolysis by Hsp70s) and also with nucleotide exchange factors to facilitate many protein-folding processes that (re)establish protein homeostasis. The Hsp70s are highly dynamic nanomachines that modulate the conformation of their substrate polypeptides by transiently binding to short, mostly hydrophobic stretches. This interaction is regulated by an intricate allosteric mechanism. The J-domain co-chaperones target Hsp70 to their polypeptide substrates, and the nucleotide exchange factors regulate the lifetime of the Hsp70-substrate complexes. Significant advances in recent years are beginning to unravel the molecular mechanism of this chaperone machine and how they treat their substrate proteins.
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Affiliation(s)
- Matthias P Mayer
- From the Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH-Alliance, 69120 Heidelberg, Germany and
| | - Lila M Gierasch
- the Departments of Biochemistry and Molecular Biology and.,Chemistry, University of Massachusetts, Amherst, Massachusetts 01003
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42
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Genest O, Wickner S, Doyle SM. Hsp90 and Hsp70 chaperones: Collaborators in protein remodeling. J Biol Chem 2018; 294:2109-2120. [PMID: 30401745 DOI: 10.1074/jbc.rev118.002806] [Citation(s) in RCA: 195] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Heat shock proteins 90 (Hsp90) and 70 (Hsp70) are two families of highly conserved ATP-dependent molecular chaperones that fold and remodel proteins. Both are important components of the cellular machinery involved in protein homeostasis and participate in nearly every cellular process. Although Hsp90 and Hsp70 each carry out some chaperone activities independently, they collaborate in other cellular remodeling reactions. In eukaryotes, both Hsp90 and Hsp70 function with numerous Hsp90 and Hsp70 co-chaperones. In contrast, bacterial Hsp90 and Hsp70 are less complex; Hsp90 acts independently of co-chaperones, and Hsp70 uses two co-chaperones. In this review, we focus on recent progress toward understanding the basic mechanisms of Hsp90-mediated protein remodeling and the collaboration between Hsp90 and Hsp70, with an emphasis on bacterial chaperones. We describe the structure and conformational dynamics of these chaperones and their interactions with each other and with client proteins. The physiological roles of Hsp90 in Escherichia coli and other bacteria are also discussed. We anticipate that the information gained from exploring the mechanism of the bacterial chaperone system will provide the groundwork for understanding the more complex eukaryotic Hsp90 system and its modulation by Hsp90 co-chaperones.
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Affiliation(s)
- Olivier Genest
- From the Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines, 13402 Marseille, France and
| | - Sue Wickner
- the Laboratory of Molecular Biology, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Shannon M Doyle
- the Laboratory of Molecular Biology, NCI, National Institutes of Health, Bethesda, Maryland 20892
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43
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Allosteric landscapes of eukaryotic cytoplasmic Hsp70s are shaped by evolutionary tuning of key interfaces. Proc Natl Acad Sci U S A 2018; 115:11970-11975. [PMID: 30397123 DOI: 10.1073/pnas.1811105115] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The 70-kDa heat shock proteins (Hsp70s) are molecular chaperones that perform a wide range of critical cellular functions. They assist in the folding of newly synthesized proteins, facilitate assembly of specific protein complexes, shepherd proteins across membranes, and prevent protein misfolding and aggregation. Hsp70s perform these functions by a conserved mechanism that relies on allosteric cycles of nucleotide-modulated binding and release of client proteins. Current models for Hsp70 allostery have come from extensive study of the bacterial Hsp70, DnaK. Extending our understanding to eukaryotic Hsp70s is extremely important not only in providing a likely common mechanistic framework but also because of their central roles in cellular physiology. In this study, we examined the allosteric behaviors of the eukaryotic cytoplasmic Hsp70s, HspA1 and Hsc70, and found significant differences from that of DnaK. We found that HspA1 and Hsc70 favor a state in which the nucleotide-binding domain (NBD) and substrate-binding domain (SBD) are intimately docked significantly more as compared to DnaK. Past work established that the NBD-SBD interface and the helical lid-β-SBD interface govern the allosteric landscape of DnaK. Here, we identified sites on these interfaces that differ between eukaryotic cytoplasmic Hsp70s and DnaK. Our mutational analysis has revealed key evolutionary variations that account for the population shifts between the docked and undocked conformations. These results underline the tunability of Hsp70 functions by modulation of allosteric interfaces through evolutionary diversification and also suggest sites where the binding of small-molecule modulators could influence Hsp70 function.
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44
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Activation of the DnaK-ClpB Complex is Regulated by the Properties of the Bound Substrate. Sci Rep 2018; 8:5796. [PMID: 29643454 PMCID: PMC5895705 DOI: 10.1038/s41598-018-24140-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 03/28/2018] [Indexed: 12/20/2022] Open
Abstract
The chaperone ClpB in bacteria is responsible for the reactivation of aggregated proteins in collaboration with the DnaK system. Association of these chaperones at the aggregate surface stimulates ATP hydrolysis, which mediates substrate remodeling. However, a question that remains unanswered is whether the bichaperone complex can be selectively activated by substrates that require remodeling. We find that large aggregates or bulky, native-like substrates activates the complex, whereas a smaller, permanently unfolded protein or extended, short peptides fail to stimulate it. Our data also indicate that ClpB interacts differently with DnaK in the presence of aggregates or small peptides, displaying a higher affinity for aggregate-bound DnaK, and that DnaK-ClpB collaboration requires the coupled ATPase-dependent remodeling activities of both chaperones. Complex stimulation is mediated by residues at the β subdomain of DnaK substrate binding domain, which become accessible to the disaggregase when the lid is allosterically detached from the β subdomain. Complex activation also requires an active NBD2 and the integrity of the M domain-ring of ClpB. Disruption of the M-domain ring allows the unproductive stimulation of the DnaK-ClpB complex in solution. The ability of the DnaK-ClpB complex to discrimínate different substrate proteins might allow its activation when client proteins require remodeling.
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45
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Voith von Voithenberg L, Lamb DC. Single Pair Förster Resonance Energy Transfer: A Versatile Tool To Investigate Protein Conformational Dynamics. Bioessays 2018; 40. [DOI: 10.1002/bies.201700078] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 12/05/2017] [Indexed: 01/23/2023]
Affiliation(s)
- Lena Voith von Voithenberg
- Department Chemie; Center for Nanoscience (CeNS); Center for Integrated Protein Science Munich (CIPSM); Nanosystem Initiative Munich (NIM); Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
- BIOSS Centre for Signalling Studies; Schänzlestr. 18 79104 Freiburg Germany
| | - Don C. Lamb
- Department Chemie; Center for Nanoscience (CeNS); Center for Integrated Protein Science Munich (CIPSM); Nanosystem Initiative Munich (NIM); Ludwig-Maximilians-Universität München; Butenandtstr. 5-13 81377 München Germany
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46
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Bap (Sil1) regulates the molecular chaperone BiP by coupling release of nucleotide and substrate. Nat Struct Mol Biol 2018; 25:90-100. [PMID: 29323281 DOI: 10.1038/s41594-017-0012-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 11/16/2017] [Indexed: 12/25/2022]
Abstract
BiP is the endoplasmic member of the Hsp70 family. BiP is regulated by several co-chaperones including the nucleotide-exchange factor (NEF) Bap (Sil1 in yeast). Bap is a two-domain protein. The interaction of the Bap C-terminal domain with the BiP ATPase domain is sufficient for its weak NEF activity. However, stimulation of the BiP ATPase activity requires full-length Bap, suggesting a complex interplay of these two factors. Here, single-molecule FRET experiments with mammalian proteins reveal that Bap affects the conformation of both BiP domains, including the lid subdomain, which is important for substrate binding. The largely unstructured Bap N-terminal domain promotes the substrate release from BiP. Thus, Bap is a conformational regulator affecting both nucleotide and substrate interactions. The preferential interaction with BiP in its ADP state places Bap at a late stage of the chaperone cycle, in which it coordinates release of substrate and ADP, thereby resetting BiP for ATP and substrate binding.
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47
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Conformation transitions of the polypeptide-binding pocket support an active substrate release from Hsp70s. Nat Commun 2017; 8:1201. [PMID: 29084938 PMCID: PMC5662698 DOI: 10.1038/s41467-017-01310-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 09/07/2017] [Indexed: 12/21/2022] Open
Abstract
Cellular protein homeostasis depends on heat shock proteins 70 kDa (Hsp70s), a class of ubiquitous and highly conserved molecular chaperone. Key to the chaperone activity is an ATP-induced allosteric regulation of polypeptide substrate binding and release. To illuminate the molecular mechanism of this allosteric coupling, here we present a novel crystal structure of an intact human BiP, an essential Hsp70 in ER, in an ATP-bound state. Strikingly, the polypeptide-binding pocket is completely closed, seemingly excluding any substrate binding. Our FRET, biochemical and EPR analysis suggests that this fully closed conformation is the major conformation for the ATP-bound state in solution, providing evidence for an active release of bound polypeptide substrates following ATP binding. The Hsp40 co-chaperone converts this fully closed conformation to an open conformation to initiate productive substrate binding. Taken together, this study provided a mechanistic understanding of the dynamic nature of the polypeptide-binding pocket in the Hsp70 chaperone cycle. Hsp70s are highly conserved molecular chaperones that play multiple essential roles in maintaining cellular protein homeostasis. Here, the authors provide structural evidence for active substrate release by Hsp70s upon ATP binding and provide insight into the molecular mechanism of ATP-driven Hsp70 chaperone activity.
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48
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Broadening the functionality of a J-protein/Hsp70 molecular chaperone system. PLoS Genet 2017; 13:e1007084. [PMID: 29084221 PMCID: PMC5679652 DOI: 10.1371/journal.pgen.1007084] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 11/09/2017] [Accepted: 10/18/2017] [Indexed: 12/21/2022] Open
Abstract
By binding to a multitude of polypeptide substrates, Hsp70-based molecular chaperone systems perform a range of cellular functions. All J-protein co-chaperones play the essential role, via action of their J-domains, of stimulating the ATPase activity of Hsp70, thereby stabilizing its interaction with substrate. In addition, J-proteins drive the functional diversity of Hsp70 chaperone systems through action of regions outside their J-domains. Targeting to specific locations within a cellular compartment and binding of specific substrates for delivery to Hsp70 have been identified as modes of J-protein specialization. To better understand J-protein specialization, we concentrated on Saccharomyces cerevisiae SIS1, which encodes an essential J-protein of the cytosol/nucleus. We selected suppressors that allowed cells lacking SIS1 to form colonies. Substitutions changing single residues in Ydj1, a J-protein, which, like Sis1, partners with Hsp70 Ssa1, were isolated. These gain-of-function substitutions were located at the end of the J-domain, suggesting that suppression was connected to interaction with its partner Hsp70, rather than substrate binding or subcellular localization. Reasoning that, if YDJ1 suppressors affect Ssa1 function, substitutions in Hsp70 itself might also be able to overcome the cellular requirement for Sis1, we carried out a selection for SSA1 suppressor mutations. Suppressing substitutions were isolated that altered sites in Ssa1 affecting the cycle of substrate interaction. Together, our results point to a third, additional means by which J-proteins can drive Hsp70's ability to function in a wide range of cellular processes-modulating the Hsp70-substrate interaction cycle.
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49
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Wieteska L, Shahidi S, Zhuravleva A. Allosteric fine-tuning of the conformational equilibrium poises the chaperone BiP for post-translational regulation. eLife 2017; 6:29430. [PMID: 29064369 PMCID: PMC5655141 DOI: 10.7554/elife.29430] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 09/01/2017] [Indexed: 12/12/2022] Open
Abstract
BiP is the only Hsp70 chaperone in the endoplasmic reticulum (ER) and similar to other Hsp70s, its activity relies on nucleotide- and substrate-controllable docking and undocking of its nucleotide-binding domain (NBD) and substrate-binding domain (SBD). However, little is known of specific features of the BiP conformational landscape that tune BiP to its unique tasks and the ER environment. We present methyl NMR analysis of the BiP chaperone cycle that reveals surprising conformational heterogeneity of ATP-bound BiP that distinguishes BiP from its bacterial homologue DnaK. This unusual poise enables gradual post-translational regulation of the BiP chaperone cycle and its chaperone activity by subtle local perturbations at SBD allosteric 'hotspots'. In particular, BiP inactivation by AMPylation of its SBD does not disturb Hsp70 inter-domain allostery and preserves BiP structure. Instead it relies on a redistribution of the BiP conformational ensemble and stabilization the domain-docked conformation in presence of ADP and ATP.
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Affiliation(s)
- Lukasz Wieteska
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Saeid Shahidi
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Anastasia Zhuravleva
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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50
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Warner JB, Ruff KM, Tan PS, Lemke EA, Pappu RV, Lashuel HA. Monomeric Huntingtin Exon 1 Has Similar Overall Structural Features for Wild-Type and Pathological Polyglutamine Lengths. J Am Chem Soc 2017; 139:14456-14469. [PMID: 28937758 PMCID: PMC5677759 DOI: 10.1021/jacs.7b06659] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Indexed: 12/22/2022]
Abstract
Huntington's disease is caused by expansion of a polyglutamine (polyQ) domain within exon 1 of the huntingtin gene (Httex1). The prevailing hypothesis is that the monomeric Httex1 protein undergoes sharp conformational changes as the polyQ length exceeds a threshold of 36-37 residues. Here, we test this hypothesis by combining novel semi-synthesis strategies with state-of-the-art single-molecule Förster resonance energy transfer measurements on biologically relevant, monomeric Httex1 proteins of five different polyQ lengths. Our results, integrated with atomistic simulations, negate the hypothesis of a sharp, polyQ length-dependent change in the structure of monomeric Httex1. Instead, they support a continuous global compaction with increasing polyQ length that derives from increased prominence of the globular polyQ domain. Importantly, we show that monomeric Httex1 adopts tadpole-like architectures for polyQ lengths below and above the pathological threshold. Our results suggest that higher order homotypic and/or heterotypic interactions within distinct sub-populations of neurons, which are inevitable at finite cellular concentrations, are likely to be the main source of sharp polyQ length dependencies of HD.
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Affiliation(s)
- John B. Warner
- Laboratory
of Molecular and Chemical Biology of Neurodegeneration, Brain Mind
Institute, Station 19, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Kiersten M. Ruff
- Department
of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Piau Siong Tan
- Structural
and Computational Biology Unit, Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Edward A. Lemke
- Structural
and Computational Biology Unit, Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Rohit V. Pappu
- Department
of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Hilal A. Lashuel
- Laboratory
of Molecular and Chemical Biology of Neurodegeneration, Brain Mind
Institute, Station 19, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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